Work vehicles such as tractors appropriately select and use various hydraulic actuators operating as traveling-system transfer devices and operating-system transfer devices.
That is, for work vehicles such as tractors, there are a plurality of specifications using different combinations of hydraulic actuators to be mounted.
Specifically, there are various specifications including: a specification including a multiplate friction-type hydraulic traveling clutch device operating as a traveling-system transfer device (see PTL 1 below; hereinafter referred to as a first prior art); a specification including a multiplate friction-type hydraulic forward/reverse-movement switching device operating as a traveling-system transfer device (see PTL 2 below; hereinafter referred to as a second prior art); and a specification including a multiplate friction-type hydraulic forward/reverse-movement switching device and a multiplate friction-type hydraulic two-wheel drive/four-wheel drive switching device (see PTL 3 below; hereinafter referred to as a third prior art).
Typically, valves for controlling actuation of a hydraulic actuator mounted in the work vehicle are collected in a valve block, and the valve block is mounted on a valve mount surface disposed on the outer surface of a housing such as a transmission case in the work vehicle.
In a conventional configuration, a dedicated valve block is prepared for each combination of the hydraulic actuators, and the valve mount surface formed on the outer surface of the housing is designed to be compatible with the arrangement, shape, and size, for example, of the dedicated valve block.
That is, in the work vehicle of the first prior art, a valve block dedicated to the first prior art is prepared, and a dedicated valve mount surface compatible with the valve block dedicated to the first prior art is formed on the outer surface of the housing.
Similarly, in the work vehicle of the second prior art, a valve block dedicated to the second prior art is prepared, and a dedicated valve mount surface compatible with the valve block dedicated to the second prior art is formed on the outer surface of the housing. In the work vehicle of the third prior art, a valve block dedicated to the third prior art is prepared, and a dedicated valve mount surface compatible with the valve block dedicated to the third prior art is formed on the outer surface of the housing.